Not sure if we have a particular preference... But we should have a script to update our list of AAGUIDs periodically (can be run by a developer)

https://fidoalliance.org/metadata/

Access the MDS3 BLOB This master registry file (JSON) contains metadata for all registered passkeys. We suggest downloading the BLOB once a month and then caching its content because the MDS data does not change often. This file is public and does not require an authorization token to fetch.

Upstreams such as https://github.com/passkeydeveloper/passkey-authenticator-aaguids/blob/main/aaguid.json and https://raw.githubusercontent.com/passkeydeveloper/passkey-authenticator-aaguids/refs/heads/main/combined_aaguid.json exist... But with questionable Software-Licensing

https://c-mds.fidoalliance.org/ is another alternative...